You guys solved it correctly. Be sure to check out my other coop maps in the "Excellent Partnership" series of mine. I promise you will have an interesting experience, especially my "Excellent Partnership 6" map.

Just before you get to the exit, there should be something that pulls you back to the turret room area.

It just feels like you put in a lot of effort in that secondary area but we don't go back to appreciate it. It's just 'boom, solved, exit'. If maybe there was one more quick/easy step to activate the lift from that other room, it might feel like one complete puzzle. Because the ending was so 'quick' I felt like I was missing another room. If that makes sense.

@VoinyxAt the time, I didn't have BEEMOD2 .2.4 alpha that has magnet portals which auto-center portal placements. I have considered updating this map and the others in the Excellent Partnership series. For now just try to be as precisely center as possible. That is the problem why the cube is apparently almost impossible.